In the co-pending application of Arthur L. Troutner Ser. No. 79,839, filed Oct. 12, 1970 now Pat. No. 3,723,230 for a CONTINUOUS PRESS FOR PRESSING GLUE-COATED CONSOLIDATABLE PRESS CHARGES, there is described a continuous press to which is fed continuously a charge comprising stacked, glue-coated wood laminae or other sheet materials. The press successfully converts this charge into a consolidated, unitary, laminar product such as gluelam beams or timbers. However, it has been found that the character and arrangement of the unconsolidated stack of sheets fed to the press has a material and critical influence on the properties of the consolidated product produced by the press.
Thus, since the continuous charge fed to the press necessarily must consist of a multiplicity of sheets of wood veneer or other material pieced together in one manner or another, it necessarily follows that the final consolidated product discharged from the press will possess a multiplicity of joints occurring at the points of contact of any two adjacent sheets. If the joints are too closely aligned with each other across the thickness of the product, or too close together longitudinally of the product, planes or areas of structural weakness are introduced. Also, any irregularity in the spacing of the joints along the length of the product introduces a corresponding irregularity in the strength qualities of the product. These factors may detract materially from the commercial application of the product.
Where the starting materials comprise wood veneer sheets, a difficulty is presented in that the sheets are fragile and break easily, particularly along the grain and in areas of defective wood. This makes difficult the problem of stacking them into a continuous press charge.
Still further, where the wood veneers are commercial veneers produced by usual manufacturing processes, they almost invariably are of different widths. The width differences are occasioned by numerous factors, including the veneer clipping routine, breakage, and shrinkage occurring in the dryer. Clipping the veneers to uniform width obviously introduces a substantial waste factor. Using veneers of random width, on the other hand, tends to produce a press charge of non-uniform thickness along its longitudinal margins. This in turn makes necessary trimming the consolidated press product to remove the defective margins, with attendant loss of material.
Another problem in the composition of a continuous press charge resides in the fact that the sheet employed as raw materials, and in particular plywood veneers, are wavy and nonplanar to a pronounced degree. Consequently unless appropriately restrained, they will not lie flat as they are stacked upon one another. The necessary effect of this property of the veneers is the composition of a stack which is unduly thick and irregular and from which the veneers tend to become dislodged as they are moved from place to place, thereby interfering with the operation of the conveyers, clogging press openings, and producing a substandard product.
Further apparent is the difficulty inherent in stacking a multiplicity of wood veneers or other sheet materials of wavy configuration, irregular widths, and subject to breakage, on a continuous basis, at a rate sufficient to sustain economical production by a cooperating continuous press.
It accordingly is the general purpose of the present invention to provide a method of assembling sheet of material, particularly wood veneers, into a continuous, linear stack of substantially uniform dimensions and qualities, adaptable for introduction into a continuous press, at a commercially feasible production rate.
It is a further object of the present invention to provide a novel laminar product resulting from the method of the invention, and to provide apparatus for its practice.